/*
 * This program is free software: you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */
package com.l2jfree.gameserver.model.drop;

import java.util.List;

import javolution.util.FastList;

import com.l2jfree.Config;
import com.l2jfree.gameserver.datatables.ItemTable;
import com.l2jfree.tools.random.Rnd;

/**
 *
 * @author  Fulminus
 */
public class L2DropCategory
{
	private final List<L2DropData> _drops;
	private int _categoryChance; // a sum of chances for calculating if an item will be dropped from this category
	private int _categoryBalancedChance; // sum for balancing drop selection inside categories in high rate servers
	private final int _categoryType;
	
	public L2DropCategory(int categoryType)
	{
		_categoryType = categoryType;
		_drops = new FastList<L2DropData>(0);
		_categoryChance = 0;
		_categoryBalancedChance = 0;
	}
	
	public void addDropData(L2DropData drop)
	{
		if (drop.isQuestDrop())
		{
			//          if (_questDrops == null)
			//              _questDrops = new FastList<L2DropData>(0);
			//          _questDrops.add(drop);
		}
		else
		{
			_drops.add(drop);
			_categoryChance += drop.getChance();
			// for drop selection inside a category: max 100 % chance for getting an item, scaling all values to that.
			_categoryBalancedChance += Math.min((drop.getChance() * Config.RATE_DROP_ITEMS), L2DropData.MAX_CHANCE);
		}
	}
	
	public List<L2DropData> getAllDrops()
	{
		return _drops;
	}
	
	public void clearAllDrops()
	{
		_drops.clear();
	}
	
	public boolean isSweep()
	{
		return getCategoryType() == -1;
	}
	
	// this returns the chance for the category to be visited in order to check if
	// drops might come from it.  Category -1 (spoil) must always be visited
	// (but may return 0 or many drops)
	public int getCategoryChance()
	{
		if (getCategoryType() >= 0)
			return _categoryChance;
		
		return L2DropData.MAX_CHANCE;
	}
	
	public int getCategoryBalancedChance()
	{
		if (getCategoryType() >= 0)
			return _categoryBalancedChance;
		
		return L2DropData.MAX_CHANCE;
	}
	
	public int getCategoryType()
	{
		return _categoryType;
	}
	
	/**
	 * useful for seeded conditions...the category will attempt to drop only among
	 * items that are allowed to be dropped when a mob is seeded.
	 * Previously, this only included adena.  According to sh1ny, sealstones are also
	 * acceptable drops.
	 * if no acceptable drops are in the category, nothing will be dropped.
	 * otherwise, it will check for the item's chance to drop and either drop
	 * it or drop nothing.
	 * 
	 * @return acceptable drop when mob is seeded, if it exists.  Null otherwise.
	 */
	public synchronized L2DropData dropSeedAllowedDropsOnly()
	{
		FastList<L2DropData> drops = new FastList<L2DropData>();
		int subCatChance = 0;
		for (L2DropData drop : getAllDrops())
		{
			if (ItemTable.isAdenaLikeItem(drop.getItemId()))
			{
				drops.add(drop);
				subCatChance += drop.getChance();
			}
		}
		
		// among the results choose one.
		int randomIndex = Rnd.get(subCatChance);
		int sum = 0;
		for (L2DropData drop : drops)
		{
			sum += drop.getChance();
			
			if (sum > randomIndex) // drop this item and exit the function
			{
				drops.clear();
				drops = null;
				return drop;
			}
		}
		// since it is still within category, only drop one of the acceptable drops from the results.
		return null;
	}
	
	/**
	* ONE of the drops in this category is to be dropped now.
	* to see which one will be dropped, weight all items' chances such that
	* their sum of chances equals MAX_CHANCE.
	* since the individual drops have their base chance, we also ought to use the
	* base category chance for the weight.  So weight = MAX_CHANCE/basecategoryDropChance.
	* Then get a single random number within this range.  The first item
	* (in order of the list) whose contribution to the sum makes the
	* sum greater than the random number, will be dropped.
	* 
	* Edited: How _categoryBalancedChance works in high rate servers:
	* Let's say item1 has a drop chance (when considered alone, without category) of
	* 1 % * RATE_DROP_ITEMS and item2 has 20 % * RATE_DROP_ITEMS, and the server's
	* RATE_DROP_ITEMS is for example 50x. Without this balancer, the relative chance inside
	* the category to select item1 to be dropped would be 1/26 and item2 25/26, no matter
	* what rates are used. In high rate servers people usually consider the 1 % individual
	* drop chance should become higher than this relative chance (1/26) inside the category,
	* since having the both items for example in their own categories would result in having
	* a drop chance for item1 50 % and item2 1000 %. _categoryBalancedChance limits the
	* individual chances to 100 % max, making the chance for item1 to be selected from this
	* category 50/(50+100) = 1/3 and item2 100/150 = 2/3.
	* This change doesn't affect calculation when drop_chance * RATE_DROP_ITEMS < 100 %,
	* meaning there are no big changes for low rate servers and no changes at all for 1x
	* servers.
	* 
	* @return selected drop from category, or null if nothing is dropped.
	*/
	public synchronized L2DropData dropOne()
	{
		int randomIndex = Rnd.get(getCategoryBalancedChance());
		int sum = 0;
		for (L2DropData drop : getAllDrops())
		{
			sum += Math.min((drop.getChance() * Config.RATE_DROP_ITEMS), L2DropData.MAX_CHANCE);
			
			if (sum >= randomIndex) // drop this item and exit the function
				return drop;
		}
		return null;
	}
}
